On both 1266 and Odins the sound stage is improved a lot over the 3xp. It's a completely different class of sound, even though the sound "signature" is very similar.I expected this to be the case, but the Arya had a major improvement to me. I also tested the He6se and did not find much improvement, but I never liked the He6se so my opinion may be colored. If anything, the He6se on the GT made it more apparent to me how much better the Susvara is than it. I felt the sound stage was a clear improvement on the Susvara and Arya with the GT, but little to no improvement on the He6se. Will be curious what others think on the He6 models.
I guess it's the dual mono design + vivids sharp presentation doing the magic.